CVE-2020-29583
Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can…
Browse: All 2020 CVEs · All vendors
- CVSS score
- 9.8 Critical
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- CISA KEV
- Yes — actively exploited (added 2021-11-03, remediation due 2022-05-03)
- Weakness (CWE)
- CWE-522
- Published
- 2020-12-22
- Last modified
- 2026-06-17
- NVD status
- Analyzed
Description
Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.
Affected products
- zyxel usg20-vpn firmware
- zyxel usg20w-vpn firmware
- zyxel usg40 firmware
- zyxel usg40w firmware
- zyxel usg60 firmware
- zyxel usg60w firmware
- zyxel usg110 firmware
- zyxel usg210 firmware
- zyxel usg310 firmware
- zyxel usg1100 firmware
- zyxel usg1900 firmware
- zyxel usg2200 firmware
Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.
Required action (CISA)
Apply updates per vendor instructions. Federal remediation deadline: 2022-05-03.
How to prioritize this
This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score. For the actively exploited vulnerabilities that matter this week, read The Exploit HQ daily security brief.
References
- http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
- https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
- https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
- https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
- https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
- https://www.zyxel.com/support/CVE-2020-29583.shtml
- https://www.zyxel.com/support/security_advisories.shtml
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583
FAQ
Is CVE-2020-29583 actively exploited?
Yes. CISA added CVE-2020-29583 to its Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03, with a federal remediation deadline of 2022-05-03. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.
What is the CVSS score of CVE-2020-29583?
CVE-2020-29583 has a CVSS base score of 9.8 (Critical). Its vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Related vulnerabilities
- CVE-2026-7273 — Zyxel GS1900 Series Switches
- CVE-2024-40891 — Zyxel DSL CPE Devices
- CVE-2024-40890 — Zyxel DSL CPE Devices
- CVE-2024-11667 — Zyxel Multiple Firewalls
- CVE-2017-6884 — Zyxel EMG2926 Routers
- CVE-2017-18368 — Zyxel P660HN-T1A Routers
Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.
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